Fin field effect transistors (FINFETs) are an interesting transistor architecture because of, for instance, their fast switching times and high current densities. A FINFET device comprises a source, a drain, and one or more fin-shaped channel structures between the source and the drain. A gate electrode over the fin(s) regulates electron flow between the source and the drain.
In WO2008/155208, a method for fabricating a field effect transistor device is disclosed. A substrate is provided having a silicon layer thereon. A fin lithography hard mask is patterned on the silicon layer. A dummy gate structure is placed over a central portion of the fin lithography hard mask. A filler layer is deposited around the dummy gate structure. The dummy gate structure is removed to reveal a trench in the filler layer, centered over the central portion of the fin lithography hard mask, that distinguishes a fin region of the device from source and drain regions of the device. The fin lithography hard mask in the fin region is used to etch a plurality of fins in the silicon layer. The trench is filled with a gate material to form a gate stack over the fins. The filler layer is removed to reveal the source and drain regions of the device, wherein the source and drain regions are intact and self-aligned with the gate stack.